Computer science students usually take a couple of classes of the electrical engineering nature. This usually involves taking some classes on binary, designing gates, designing multiplexors, etc.
When I took classes on these subjects, I did not have many options for free software to make diagrams of the above items.
I recently discovered an online application that allows you to produce electrical diagrams for free. You can also use it for other types of diagrams. It could be a very useful application for computer science students.